Scientists test-drive new machine

09 October 2006

Researchers at UCT and Stellenbosch University are collaborating on a new device for use in Near Infrared Spectroscopy (NIRS).

NIRS works on the principle that light penetrates several centimetres of biological tissue. This principle is demonstrated by a simple experiment. When holding a hand against a bright white light, the hand glows red. The colour is caused by haemoglobin, the pigment found in red blood cells.

Depending on the concentration of oxygenated and deoxygenated blood, a certain amount of light will be reflected. The principle also works for brain spectroscopy. You can then work out which part of the brain is active by using special software that shows colour mapping of oxygenated blood. The software constructs a 3D colour image of the measurements taken with the DYNOT (Dynamic Optical Tomography) machine.

This is the only machine of its kind in Africa and is housed at Tygerberg Hospital.

AT UCT, Frances Robertson, a PhD student in biomedical engineering, is involved in the analysis of the images to tell where in the brain activity is taking place. Her supervisors are Dr Ernesta Meintjes and Dr Tania Douglas of the Department of Human Biology, while other members of the UCT team include Lester John.

This technology is revolutionary for the study of brain activity in patients with stress and anxiety related disorders. For the studies, a set of patients undergoes NIRS scanning while doing some cognitive or emotional task, like looking at emotive pictures.

"An analysis of the NIRS images may then show that the control group has a certain change in brain activity in a particular location of the brain, and that the psychiatric patients have more or less than the control group, or no change," says Robertson. "This type of information could help researchers understand brain activity related to anxiety and stress, or other disorders, and also help them to research treatments for these disorders."

Researchers with UCT's Medical Research Council (MRC) Research Unit on Medical Imaging are working hand in hand with colleagues at Stellenbosch's MRC Research Unit on Anxiety and Stress Disorders. The collaboration falls under the Cross-University Brain-Behaviour Initiative (CUBBI), which is focused on understanding vulnerability and resilience after trauma.